Speed reducer and motion translator

ABSTRACT

This disclosure relates to a power transmitting device which serves as a special application speed reducer and may be utilized as a motion translator, converting rotary to linear motion for example. The device includes a movable driven member, a bearing member having a surface generally parallel to a surface of the driven member and adapted to move in unison therewith, and a generally cylindrical drive member disposed between the parallel surfaces of the bearing and driven members and in bearing contact therewith. In the disclosed device, the coefficient of friction of the members are chosen such that the drive means frictionally grips the driven member and slips against the bearing member to cause the members to move in unison. Where the surfaces are generally flat, for example, the rotational movement of the drive means is converted to linear movement, however relatively complex motions are also easily produced by the disclosed device.

United States Patent Sommer [4 1 Aug. 29, 1972 Warren T. Sommer, 601Orleans, Detroit, Mich. 48207 [22] Filed: Oct. 5, 1970 [21] Appl. No.:77,830

[72] Inventor:

[52] US. Cl ..74/25, 74/ 190 [51] Int. Cl ..Fl6h 21/16 [58] lfi'eld ofSearch ..74/190, 204, 215, 25, 203, 74/204, 206

[56] References Cited UNITED STATES PATENTS 2,602,338 7/ 1952 Opocenskyet al. ..74/ 198 1,715,637 6/ 1929 Brandstetter ..74/204 2,461,258 2/1949 Brooks ..74/193 3,400,599 9/1968 Samuta ..74/194 3,424,012 l/1969l-lirmann ..74/25 3,475,972 1 1/ 1969 Steibel ..74/25 3,572,136 3/ 1971Stanley ..74/25 2,940,322 6/1960 Uhing ..74/25 2,602,339 7/ 1952 Moen..74/206 2,732,724 1 /1956 Tateishi ..74/206 2,912,868 11/ 1959 Preskitt..74/25 3,199,371 8/1965 Lins et a1 ..........74/664 FOREIGN PATENTS ORAPPLICATIONS 769,076 2/ 1957 Great Britain ..74/215 PrimaryExaminer-William F. ODea Assistant ExaminerWesley S. Ratliff, Jr.Att0rneyRaymond E. Scott [57] ABSTRACT This disclosure relates to apower transmitting device which serves as a special application speedreducer and may be utilized as a motion translator, converting rotary tolinear motion for example. The device includes a movable driven member,a bearing member having a surface generally parallel to a surface of thedriven member and adapted to move in unison therewith, and a generallycylindrical drive member disposed between the parallel surfaces of thebearing and driven members and in bearing contact therewith. In thedisclosed device, the coefficient of friction of the members are chosensuch that the drive means frictionally grips the driven member andslips'against the bearing member to cause the members to move in unison.Where the surfaces are generally flat, for example, the rotationalmovement of the drive means is converted to linear movement, howeverrelatively complex motions are also easily produced by the discloseddevice.

13 Claims, 7 Drawing Figures Patented Aug. 29, 1972 3,686,962 V 2Sheets-Sheet 1 INVENTOR 4 0/75! 7, Jaw/27W" BY EQ BALXAX ATTORNEYPatented Aug. 29, 1972 3,686,962

- 2 Sheets-Sheet 2 INVENTOR lVUf/Ffi Z' Jam/27.4w

ATTORNEY SPEED REDUCER AND MOTION TRANSLATOR DESCRIPTION OF THE PRIORART motors are inexpensive and relatively small. Such devices arehowever generally designed to operate at a slower speed than the powerinput and the final motion may be complicated and irregular. The speedreduction and motion translation is normally achieved by gears, cams,pulleys and the like which are subject to failure and which may addsubstantial cost to the device. It is an object of the present inventionto provide a relatively inexpensive motion translator and speed reducerwhich is more versatile than any known device.

SUMMARY OF THE INVENTION The speed reducer and motion translator of thisinvention includes a driven member, a bearing member having a surfacegenerally parallel to a surface of the driven member, and a generallycylindrical drive member disposed between the parallel surfaces of thebearing and driven members, in bearing contact therewith. The termssurface and surfaces are used herein in the broad sense, and includeedge contacts. The drive member of the device is adapted to slip againstthe bearing member, but grip the driven member, such that the bearingand driven members will move in unison, as the drive member is rotatedthereagainst, if they are restrained from relative movement. In thedisclosed embodiments of the invention, the material of the members arechosen such that the drive member will frictionally grip the drivenmember and slip against the bearing member. I have also found itpreferable to utilize a resilient material for the driven member, suchthat the driven member is resiliently deformed as the drive member isrotated thereagainst.

The disclosed embodiments of the invention include a cylindrical speedreducer, wherein the drive member is received between an outer annularmember and a concentric cylindrical member, causing the members torotate in the direction of the drive member, but at a slower speed.Another embodiment includes a bearing member and driven member havinggenerally linear surfaces, wherein the rotary motion of the drive memberis converted or translated to linear motion. It is also possible toproduce relatively complex motions, as shown by another embodiment ofthe invention wherein the parallel surfaces include concave and convexportions. It can be seen that the speed reducer and motion translator ofthis invention is relatively simple, but is quite versatile, and may beutilized to produce a variety of motions.

Other advantages and meritorious features of this invention will morefully appear from the following descriptions, claims, and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation of abattery operated power transmission assembly utilizing the invention asa speed reducer;

FIG. 2 is a side elevation of the embodiment of the speed reducer shownin FIG. 1;

FIG. 3 is a side elevation of another embodiment of the invention;

FIG. 4 is a side elevation of another embodiment of I the invention,utilized as a motion translator;

FIG. 5 is a side elevation of another embodiment of the inventionutilized as a motion translator;

FIG. 6 is a top elevation of another embodiment of the inventionutilized to drive an endless belt; and

FIG. 7 is a side elevation of another embodiment of the inventionutilized in a cam assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The power transmission assemblyshown in FIG. 1 includes an electric motor 20 powered by a battery 22,.which drives the speed reducer of this invention, indicated generally at24 and shown in FIG. 2. The motor may be a conventional high speedmotor, such as used on battery powered toys and display devices. Themotor includes a drive shaft 26 and is electrically connected to thebattery by wires or leads 28. The battery may be a conventionalflashlight battery, for example.

This embodiment of the speed reducer of this invention is a frictiondrive unit wherein the motor drive shaft 26 is received between theresilient annular driven member 30 and the cylindrical bearing member32, in bearing engagement therewith. The coefficient of friction of themembers, in this embodiment, are chosen such that the drive member orshaft 26 frictionally grips the surface of the annular driven member 30and slips against the bearing member 32. The resilient deformation ofthe driven member 30 aids in gripping the drive shaft by increasing thecontact area and, in this embodiment, the resiliency of the drivenmember also causes the driven and bearing members to move or rotate inunison when the drive shaft is rotated. A suitable material for thedriven member is rubber or synthetic rubber, for example, and Teflon orother friction resistant material may be used for the bearing member.Various plastic or metal materials may be used for the drive shaft whichmay be relatively rigid or flexible. It will be understood however thatvarious materials may be utilized for thecomponents of the disclosedembodiments of the invention, provided the drive shaft grips the drivenmember and slips against the bearing member. It may even be possible toprovide mating teeth on the drive shaft and driven member.

Rotation of the drive shaft 26 causes the driven member 30 to rotate inthe same direction as the drive shaft, but at a substantially slowerrate due to the difference in diameters of the drive shaft and drivenmember. The resilient driven member closely conforms to external surfaceof the bearing member and frictionally retains the bearing member due tothe substantially larger contact'area, causing the bearing member torotate in unison therewith. The driven member in this embodiment isprovided with a cross-shaped gear extension 34 which may be utilized todriven another member, not shown, such as a mechanized toy or displaydevice. The gear extension is adapted to be received within the devicedriven by the speed reducer and supports the speed reducer assembly.

The embodiment of the invention shown in FIG. 3 is a motor reducer andmotion translator, wherein the device 40 is adapted to move linearlyalong the rotatable drive member or shaft 42. The device issubstantially the same as the speed reducer 24 shown in FIG. 2 andincludes a resilient annular driven member 44, and a cylindrical bearingmember 46. The bearing member includes a cylindrical extension or shaft48,'which may be integral with the bearing member or a separate shaft.In this embodiment, the drive shaft 42 and shaft 48 extend beyond bothends of the device 40. Rotation of the drive shaft causes the drivenmember and bear ing member to rotate in the same direction as the driveshaft, at a slower rate, as described above. The device-is caused tomove linearly on the drive shaft by applying a force to one end of theshaft 48, as illustrated schematically by arrow 50 in FIG. 3. The force,which in this embodiment is generally perpendicular to ,the axis of theshaft 48, tends to skew the driven member on the drive shaft, as shownin phantom, causing the device to .move linearly in the direction ofarrow 52. The linear motion may be reversed merely by applying a similarforce to the opposite end of the shaft or reversing the direction ofrotation of the drive shaft. The same result may also be obtained bydesigning the device such that the drive shaft and the engaging surfacesof the members are angularly related, similar to turning a rotatingwheel on a surface. For example, the bearing, member may define ahyperbola of revolution, wherein the diameter is greater at the endsthan the midportion, and the external driven member closely conformsthereto and is resiliently deformed by the driven shaft which isrotatably received between the opposed surfaces of the members. In thisembodiment, the device will move linearly as it rotates withoutrequiring an additional external force.

The embodiment of the device 60 shown in FIG. 4 is a motion translator,and is shown primarily to illustrate the relatively complex motionswhich may be achieved with the device of this invention. In thisembodiment, the internal member 62 is preferably the resilient drivenmember and the bearing member 64 is the external member. The driven andbearing members may also be reversed in the embodiment shown in FIG. 1,for example, without changing the operation of the device. The rotatabledrive shaft 66 is received between the opposed generally parallelsurfaces of the driven and bearing members and is resiliently urgedagainst the bearing member 64 by the resiliently deformable drivenmember 62. This embodiment of the invention utilizes a connecting rod 68to support and orientate the members, rather than an axial shaft, whichis movably received in a bearing member 70. Rotation of the drive shaft66, which in this embodiment has a fixed axis of rotation, causes thedriven and bearing members to shift in the direction of rotation, suchthat the members shift horizontally and vertically on the drive shaft.The connecting rod 68 follows the motion of the members in the bearing,defining a heart-shaped motion.

The embodiment of the motion translator shown in FIG. is adapted toshift the driven member 80 and bearing member 82 linearly in response torotation of the drive shaft 84. The operation of the device issubstantially' as described above, wherein the drive shaft frictionallygrips the resiliently deformable driven member 80, causing the drivenmember to shift in the direction of rotation of the drive shaft. Thedriven shaft is resiliently urged against the bearing member by thedriven member, which must be fixed in relation to the driven member,such that the members shift linearly in unison. The driven member slipsagainst the bearing member as described above. The members may be fixedrelative to each other by a securement at the ends or a pair of magnets,not shown, may be secured to the members adapted to continually urge themembers together.

The embodiment of the speed reducer and motion translator shown in FIG.6 is adapted to drive a rotatable drum or pulley 92. The driven-member94 in this embodiment is a resilient flexible belt 94 which is .receivedover the rotatable drive shaft 96 and the driven member 98. The drivenmember 98 is rotatably supported on shaft 100 and the pulley-92 isrotatably supported on shaft 102. The drive shaft 96 frictionally gripsthe resilient belt 94 to shift the belt in the direction of rotation ofthe drive shaft, as described above. The cylindrical bearing member andpulley are thus caused to rotate as described above. The devicefunctions substantially as described above, however FIG. 6 illustratesanother use for the speed reducer and motion translator of thisinvention.

The speed reducer and motion translator shown in FIG. 7 functions as avariable speed cam and may be utilized to actuate various devicesincluding switching mechanisms. In this embodiment, the driven memberindicated generally at includes a resilient layer 122, such as syntheticrubber, and a relatively rigid layer 124 which supports the integral camportion 126. A rotatable drive member is received between theresiliently deformable layer 122 of the driven member and thecylindrical bearing member 130. The device is supported in thisembodiment on a central shaft 132. A bearing member 134 is continuallyurged against the cam portion 126 of the device by a spring 136 and isadapted to move linearly within a conventional bearing 138. It can'beseen from FIG. 7 that the loading of the cam portion by the bearingmember 134 will vary according to the position of the cam and will begreatest when the cam is in the position shown in FIG. 7.

In each of the disclosed embodiments of the invention, there is apredetermined energy loss proportional to the deformation of the drivenmember, however this energy loss has been minimized in the cam assemblyshown in FIG. 7. In this embodiment the energy loss is maximum at thecam position shown, wherein the bearing 134 exerts the greatest pressureagainst the cam 126, which deforms the resilient layer 122 of the drivenmember. The energy loss is however reduced as the cam portion 126rotates, because the bearing 134 is spring biased against the cam,resulting in a more efficient operation.

It can be seen from the embodiments of the invention describedhereinabove that relatively complex motions may be generated by thespeedreducer and motion translator of this invention although the translatormechanism is relatively simple. An important feature of the motiontranslator device described hereinabove is that the drive shaft isrelatively small compared to the driven and bearing members, permittingthe drive member to follow the configuration of the driven and bearingmembers. It is also important to note that because of the supportprovided by the bearing surface, I

the rotating drive member does not have to transmit bending forces alongits length normally required to maintain contacts between the elementsof a drive mechanism. The rotating drive member may therefore be thinnerand more flexible than is normally required.

What is claimed is:

1. A device of the character described, comprising: a movable bearingmember, a driven member operably attached to said bearing member andadapted to move in unison therewith and having a surface generallyparallel to an opposed surface of the bearing member, one of saidmembers being resiliently deformable with its surface having arelatively high coefficient of friction, the surface of the opposedmember having a relatively low coefficient of friction, and a rotatable,generally cylindrical drive means disposed between said parallelsurfaces of the members in bearing engagement with said surfaces andresiliently deforming said one of said members, said drive means adaptedto grip the engaging surface of said one of said members and slipagainst the surface of said opposed member to drive said members inunison when said drive means is rotated.

2. The invention defined in claim 1, characterized in that one of saidmembers has a generally cylindrical surface and the other member has anopposed, generally concentric, parallel cylindrical surface.

3. The invention defined in claim 1, characterized in that one of saidmembers is annular, the other member is generally cylindrical andreceived within the annular member, and said drive means is disposedbetween the opposed cylindrical surfaces of said members in bearingcontact therewith.

4. The invention defined in claim 3, characterized in that the distancebetween the opposed parallel surfaces of said members is normally lessthan the diameter of said drive means, compressing said drive meansbetween said opposed surfaces.

5. The invention defined in claim 1, characterized in that the parallelsurfaces of said members are generally linear, converting the rotationalmotion of said drive means to a linear motion of said members, and aretention means adapted to cause the members to move in unison.

6. The invention defined in claim 1, characterized in that said drivenmember has a greater coefficient of friction than sad bearing member,causing the drive means to frictionally grip said driven member and slipagainst said bearing member.

7. The invention defined in claim 6, characterized in that said drivenmember is resiliently deformable and the distance between the opposedsurfaces of said members, in their relaxed state, is less than thediameter of said drive means.

8. A speed reducer unit, comprising: A resilient movable driven member,a relatively rigid movable bearing member having a surface generallyparallel to a surface of the driven member and adapted to move in unisontherwith and a rotatable, generally cylindrical drive member disposedbetween said generally parallel slips against said bearing member andfrictionally grips said driven member to shift said driven and bearingmembers in unison.

9. The speed reducer unit defined in claim 8, characterized in that theresiliency of said driven member biases said driving member against thebearing member and retains the driving member in said bearing contact.

10. The speed reducer unit defined in claim 8, characterized in that thediameter of said driving member is relatively small compared to thewidth of said parallel surfaces.

11. The speed reducer unit defined in claim 8, characterized in that theparallel surfaces of said driven and bearing members are generallycylindrical.

12. The speed reducer unit defined in claim 11, characterized in thatsaid driven member is generally cylindrical and said bearing member isannular and receives said driven member therein.

13. The speed reducer unit defined in claim 8, characterized in thatsaid generally parallel surfaces include convex and concave portions.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,686,962 August29, 1972 Patent No. Dated Inventor(5) Warren T. Sommer 7 It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

On the cover sheet (72) 601 Orleans, Detroit, Mich. b.8207" should read17130 Sunset, Detroit, Mich. 14.8212

Signed and sealed this 15th day of May 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GO'ITSCHALK Attesting Officer Commissionerof Patents FORM P040530 (10-69) USCOMM-DC 60376-P69 Q U,S. GOVERNMENTPRINTING OFFICE: 19! 0-366-334,

1. A device of the character described, comprising: a movable bearingmember, a driven member operably attached to said bearing member andadapted to move in unison therewith and having a surface generallyparallel to an opposed surface of the bearing member, one of saidmembers being resiliently deformable with its surface having arelatively high coefficient of friction, the surface oF the opposedmember having a relatively low coefficient of friction, and a rotatable,generally cylindrical drive means disposed between said parallelsurfaces of the members in bearing engagement with said surfaces andresiliently deforming said one of said members, said drive means adaptedto grip the engaging surface of said one of said members and slipagainst the surface of said opposed member to drive said members inunison when said drive means is rotated.
 2. The invention defined inclaim 1, characterized in that one of said members has a generallycylindrical surface and the other member has an opposed, generallyconcentric, parallel cylindrical surface.
 3. The invention defined inclaim 1, characterized in that one of said members is annular, the othermember is generally cylindrical and received within the annular member,and said drive means is disposed between the opposed cylindricalsurfaces of said members in bearing contact therewith.
 4. The inventiondefined in claim 3, characterized in that the distance between theopposed parallel surfaces of said members is normally less than thediameter of said drive means, compressing said drive means between saidopposed surfaces.
 5. The invention defined in claim 1, characterized inthat the parallel surfaces of said members are generally linear,converting the rotational motion of said drive means to a linear motionof said members, and a retention means adapted to cause the members tomove in unison.
 6. The invention defined in claim 1, characterized inthat said driven member has a greater coefficient of friction than saidbearing member, causing the drive means to frictionally grip said drivenmember and slip against said bearing member.
 7. The invention defined inclaim 6, characterized in that said driven member is resilientlydeformable and the distance between the opposed surfaces of saidmembers, in their relaxed state, is less than the diameter of said drivemeans.
 8. A speed reducer unit, comprising: A resilient movable drivenmember, a relatively rigid movable bearing member having a surfacegenerally parallel to a surface of the driven member and adapted to movein unison therwith, and a rotatable, generally cylindrical drive memberdisposed between said generally parallel surfaces of said driven andbearing members in bearing contact therewith and resiliently deformingsaid driven member, said bearing member surface having a relatively lowcoefficient of friction, compared to said driving and driven members,such that said driving member slips against said bearing member andfrictionally grips said driven member to shift said driven and bearingmembers in unison.
 9. The speed reducer unit defined in claim 8,characterized in that the resiliency of said driven member biases saiddriving member against the bearing member and retains the driving memberin said bearing contact.
 10. The speed reducer unit defined in claim 8,characterized in that the diameter of said driving member is relativelysmall compared to the width of said parallel surfaces.
 11. The speedreducer unit defined in claim 8, characterized in that the parallelsurfaces of said driven and bearing members are generally cylindrical.12. The speed reducer unit defined in claim 11, characterized in thatsaid driven member is generally cylindrical and said bearing member isannular and receives said driven member therein.
 13. The speed reducerunit defined in claim 8, characterized in that said generally parallelsurfaces include convex and concave portions.